Conventionally, Group III nitride semiconductor light-emitting devices, such as light-emitting diodes (LEDs) which emit short-wavelength light of blue band or green band and laser diodes (LDs), utilize a light-emitting layer of gallium indium nitride (GaYInZN: 0≦Y, Z≦1, Y+Z=1) (JP-B SHOO 55-3834, for example). A light-emitting portion is formed such that two clad layers made of Group III nitride semiconductors having different electric conductive types are disposed on both sides, respectively, of the light-emitting layer. The clad layer for forming the light-emitting portion of such a double hetero (DH) structure is made of aluminum gallium nitride (AlXGaYN: 0≦X, Y≦1, X+Y=1).
The stacked structure for forming the Group III nitride semiconductor light-emitting device of pn junction type DH structure that has a light-emitting portion of DH structure having such a light-emitting layer between an n-type clad layer and a p-type clad layer is formed using mainly sapphire (α-Al2O3 monocrystal) or silicon carbide (SiC) monocrystal as a substrate. This is because such material has optical transparency allowing light from the light-emitting layer to pass and has heat resistance capable of withstanding crystal growth of the Group III nitride semiconductor layer which requires high temperature. In the case of the conventional Group III nitride semiconductor light-emitting device, the substrate used for forming the stacked structure for the light-emitting device is generally left standing as a plate body for mechanically supporting the stacked structure even after the device forming step.
The Group III nitride semiconductor light-emitting device with the substrate made of crystal, such as sapphire, remaining thereof is suitable for maintaining the mechanical supporting force for the stacked structure, but since the sapphire is electrically insulative, the device must be processed into a flip chip type or two-bonding type. In the case of the flip chip type, it is troublesome to process the device, and in the case of the two-bonding type, the wiring including wire bonding is troublesome. Thus, there is a problem that the productivity at the time of mounting operation is deteriorated.
The present invention has been accomplished in view of the above circumstances, and it is an object of the invention to provide a Group III nitride semiconductor light-emitting device in which the productivity at the time of mounting operation is excellent while maintaining a mechanical supporting force of a substrate. It is also an object of the invention to provide a method of producing the Group III nitride semiconductor light-emitting device and an LED lamp.